1. Field of the Invention
The present invention relates to a data communication apparatus, and specifically relates to a data communication apparatus such as an internet facsimile apparatus and the like for performing facsimile communications over an internet line.
2. Description of the Related Art
In data communication apparatuses for transmitting data using a telephone line such as facsimile apparatuses and the like, the problem of poor operationality arises relating to the time and transmission cost incurred when transmitting large amounts of data due to the small line capacity of the telephone line.
For this reason even though a document image generally is read at fine detail, i.e., a high resolution of 600 dpi, the data actually are transmitted as low detail data after conversion to data of, for example, low resolution of 200 dpi.
Since only the culled data are transmitted at low resolution, however, the obtained high resolution image data are not used, which is extremely wasteful. In particular, the receiving side may desire to receive the high resolution (fine detail) data, not the low resolution data.
In view of this situation, the rapid popularization in recent years of internet facsimile apparatuses capable of sending and receiving data not only over telephone line by also using an internet line has led to the idea of transmitting large amounts of fine detail data using an internet line. This idea provides excellent transmission speed and cost perspectives when transmitting large amounts of data because an internet line is a large capacity line compared to a telephone line.
On the other hand, although data are transmitted using an internet line in such internet facsimile apparatuses, a new disadvantage arises inasmuch as a sender cannot know when data are received because data reception does not occur at the same time as data transmission.
Accordingly, there is the further inconvenience that even when the fine detail data are transmitted by the sending side, the reliable reception of the fine detail data cannot be immediately confirmed.
Moreover, there are also instances when fine detail data are unnecessary and low detail data are adequate on the receiving side, but the receiving side desires reliable reception simultaneously with the transmission by the sending side, and in such instances also the transmission of fine detail data over an internet line is more inconvenient.